A semiconductor laser driving device includes a current supply unit supplying current to a semiconductor laser; a first control unit controlling the current supply unit to supply a first current which is half or less of a lasing threshold of the semiconductor laser; and a second control unit controlling the current supply unit to supply a second current which is larger than the lasing threshold after a first time is passed from an edge of a clock signal.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A semiconductor laser driving device, comprising: a current supply unit supplying current to a semiconductor laser; a first control unit controlling said current supply unit to supply a first current which is half or less of a lasing threshold of the semiconductor laser; a second control unit controlling said current supply unit to supply a second current which is larger than the lasing threshold after a first time is passed from an edge of a clock signal; an input unit inputting a signal representing light-emission intensity of the semiconductor laser, and a signal representing a second time from the edge of the clock signal to a start of light-emission of the semiconductor laser; a first decision unit deciding the first current based on the difference between the first and second times, the first current being the half or less of the lasing threshold; a second decision unit deciding the sum of the first and second current based on the light-emission intensity; and a third decision unit deciding the second current based on the sum and the decided first current.
3. An optical head, comprising a semiconductor laser driving device according to claim 1 .
4. An optical disk device, comprising a semiconductor laser driving device according to claim 1 .
5. A semiconductor laser driving method, comprising: supplying a first current which is half or less of a lasing threshold to a semiconductor laser; and supplying a second current which is larger than the lasing threshold to the semiconductor laser after a first time is passed from an edge of a clock signal; inputting a signal representing light-emission intensity of the semiconductor laser, and a signal representing a second time from the edge of the clock signal to a start of light-emission of the semiconductor laser; deciding the first current based on the difference between the first and second times, the first current being the half or less of the lasing threshold; deciding the sum of the first and second current based on the light-emission intensity; and deciding the second current based on the sum and the decided first current.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
December 26, 2007
March 30, 2010
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